The present invention relates to an optical device, and an optical connector, electronic device, and electronic equipment using it, and is particularly suitable for electronic equipment such as audio visual (AV) equipment and security equipment for a home network or on-vehicle network.
Conventionally, there has been an optical device in which a light emitting element and a light-receiving element are mounted on a board. In this optical device, positions of the light-emitting element and light-receiving element, and orientations of the light-emitting surface of the light-emitting element and the light-receiving surface of the light-receiving element are fixed. Optical connectors using such an optical device vary in shape depending on use or specification even if they have quite identical functions, so that many kinds of optical devices should be designed and produced in accordance with the specifications of the optical connectors, which causes high cost and low productivity.
The applicant proposes in this application that a flexible board is used as a means for solving such a problem, while there has conventionally been a mounting technology using a flexible board as described below.
A conventional first mounting technology using a flexible board is used for a concatenated sensor in which multiple sensors, ICs, etc. are mounted on a flexible board to detect a fixed width (see JP 4-184831 A, for example) This concatenated sensor is made in such a manner that its electronic components are mounted on a tape-like flexible board at predetermined intervals with a common power line, and are covered with a housing molded out of soft synthetic resin. In this concatenated sensor, the electronic components per se have functions of sensors or lighting devices, and are protected from dust, etc. without impairment of the functions by the housing molded out of soft synthetic resin.
Furthermore, a conventional second mounting technology using a flexible board is a high density mounting technology of covering a flexible board, on which a semiconductor memory is mounted, with silicon resin (see JP 2002-270733 A, for example).
However, the conventional first and second mounting technologies using a flexible board, in which the optical semiconductor elements (light-emitting element and light-receiving element) mounted on the flexible board are encapsulated, do not ensure that light from the optical semiconductor is effectively let out, and that light is effectively let in to the optical semiconductor.
Furthermore, there has been an electronic device in which a molded resin member is mounted on a flexible board (see JP 9-102654 A, for example).
In this electronic device, a photosensor encapsulated in resin in advance is electrically connected to a flexible board by soldering or other means, and then a molded resin member is formed by injection molding so as to cover the gap between the photosensor and the flexible board and part of the flexible board. Furthermore, the molded resin member for covering the wiring patterns provided on the flexible board is provided with a protection protrusion having a thickness gradually decreasing in the direction of projection of the wiring pattern. According to the molded resin member technology described above, portions of the flexible board on which no molded resin member is provided are bent easily because of flexibility thereof, while the wiring pattern portion of the flexible board is provided with the protection protrusion having a thickness gradually decreasing in the direction of projection of the wiring pattern, so that no bending stress is locally applied to the wiring pattern, thereby preventing the wiring pattern from breaking.
However, the molded resin member of the conventional electronic device described above is made, after the flexible board on which a photosensor is mounted is held by a mold for injection molding and pressurized, by injecting thermoplastic resin into the mold. The technology of making the molded resin member is not a technology to be applied to transfer molding. Furthermore, the clamping pressure of a mold at transfer molding is generally several-fold larger as compared with the clamping pressure of the mold at injection molding, so that the pressure applied to the flexible board and the wiring pattern when clamped by the mold at transfer molding should be reduced.